A. Raymond et al., PALYNOLOGY AND PALEOECOLOGY OF LIGNITES FROM THE MANNING FORMATION (JACKSON GROUP) OUTCROP IN THE LAKE SOMERVILLE SPILLWAY OF EAST-CENTRAL TEXAS, International journal of coal geology, 34(3-4), 1997, pp. 195-223
Four palynomorph assemblages, whose parent plants contributed to the f
ormation of the lignite, occur in the lignite seams and associated sed
iments from the Manning Formation (Jackson Group) outcrop in the Lake
Somerville spillway of Texas. The Cicatricosisporites-Laevigatosporite
s fern assemblage occurs in the middle and upper seam and probably der
ived from a freshwater herbaceous mire community. The Momipites corylo
ides-Arecipites columellus-Liliacidites assemblage occurs in all three
seams and probably derived from a freshwater mire forest with an open
canopy or shrub community. The Momipites coryloides-Nyssa-Rhoipites a
ngustus assemblage occurs in the lower and middle seams and probably d
erived from a different freshwater mire forest. The Cupuliferoipolleni
tes-Cupuliferoidaepollenites liblarensis-Siltaria cf. S. scabriextima
assemblage occurs at the top of the lower and middle seams, which are
overlain by marine sediments. The association between Cupuliferoipolle
nites dominance and the presence of marine diatoms and brackish or mar
ine trace fossils in the lignite suggests that this assemblage may hav
e derived from a mangrove (i.e. marine or brackish) mire forest. Howev
er, other factors may influence its distribution. Ailanthipites berryi
, possibly derived from a tree or shrub related to the 'tree of heaven
', predominates in the claystone underlying the lower lignite seam and
may have colonized the coastal plain prior to the initiation of peat
accumulation. We can differentiate lignite samples dominated by fern s
pores, Momipites pollen and Cupuliferoipollenites pollen based on gas
chromatography-mass spectrometry (GC-MS) fragmentograms of triterpanes
(m/z 191) and steranes (m/z 217), The lignite layers dominated by eac
h palynomorph assemblage appear to have distinct sources and different
early diagenetic (pre-coalification) histories. (C) 1997 Elsevier Sci
ence B.V.